One of the most important properties of tests is reproducibility. For tests to be reproducible, the same environment should be set on each test invocation. When it comes to memory content, this is not exactly the case in kvm-unit-tests. The tests might, mistakenly or intentionally, assume that memory is zeroed (by the BIOS or KVM). However, failures might not be reproducible if this assumption is broken. As an example, consider x86 do_iret(), which mistakenly does not push SS:RSP onto the stack on 64-bit mode, although they are popped unconditionally on iret. Do not assume that memory is zeroed. Clear it once it is allocated to allow tests to easily be reproduced. Reviewed-by: Krish Sadhukhan <krish.sadhukhan@xxxxxxxxxx> Signed-off-by: Nadav Amit <nadav.amit@xxxxxxxxx> --- lib/alloc_page.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/lib/alloc_page.c b/lib/alloc_page.c index 730f2b5..97d1339 100644 --- a/lib/alloc_page.c +++ b/lib/alloc_page.c @@ -65,6 +65,8 @@ void *alloc_page() freelist = *(void **)freelist; spin_unlock(&lock); + if (p) + memset(p, 0, PAGE_SIZE); return p; } @@ -126,6 +128,8 @@ void *alloc_pages(unsigned long order) } } spin_unlock(&lock); + if (run_start) + memset(run_start, 0, n * PAGE_SIZE); return run_start; } -- 2.17.1
